This is the horrifying moment a stage collapsed during a storm last night at the Indiana State Fair, killing at least five people and injuring dozens more.

Fans screamed hysterically after strong winds caused the stage rigging for the outdoor concert to collapse on top of them shortly before 9pm as a country music band were about to perform.

Emergency crews were called to the scene to tend to those trapped beneath the stage and workers set up a command centre to treat to those who were injured. Children are said to have been among 45 people who were badly hurt.

Scroll down for video

Horror: The moment strong winds caused the stage rigging for the outdoor concert to collapse at the fairground in Indianapolis

Thousands of concert-goers were being evacuated to a nearby building because of high winds of up to 60 mph (96 km/h) when the rigging for the stage fell onto the track where some were seated.

'It was like it was in slow motion,' concert-goer Amy Weathers told the Indianapolis Star. 'You couldn't believe it was actually happening.'

Those who were injured were being moved to a tunnel below the stage, the Star reported. A hole was being dug to try to reach those trapped beneath the rigging.

Tragic: Pretty Alina, a teacher, was killed when the stage collapsed on top of her

One of those killed was stagehand Nate Byrd, 51, who was on the rigging to run the show's spotlight.

Mr Byrdwas crushed after he fell to the ground with the stage and died on Sunday at Methodist Hospital.

Also killed on the scene were Tammy Vandam, 42, of Wanatah, Indiana; Glenn Goodrich, 49, of Indianapolis; Alina BigJohny, 23 of Fort Wayne and Christina Santiago, 29, of Chicago, according to the Marion County Coroner's office.

Alina, a 23-year-old teacher, can be seen in pictures happily smiling for the camera before the accident claimed her young life.

Activist: Christina Santiago leaves behind a long-term partner after she was hit by the falling stage

Fell: Construction worker Nathan Byrd was up on top of the rigging, running a spotlight, when the stage collapsed

Other shots show Christina Santiago, 29, who also died in the accident.

Miss Santiago was manager of programming for the Lesbian Community Care Project at Howard Brown Health Center, in Chicago.

She leaves behind a long-term girlfriend.

'It’s a tragic moment,' Todd Taylor, a neighbour of Santiago and her partner, said. 'They’re good people. They had two pets they loved and adored. They were very much in love with each other. For this to happen with them being so young is tragic.'

Crushed: Glenn Goodrich, 49, of Indianapolis, will be missed by his colleagues at Ikelite

A 17-year-old boy may never walk again after his back was broken in the accident, his mother said.

The lead singer of the country duo Sugarland said she has watched recaps of last night's deadly stage collapse with horror and 'there are no words to process a moment of this magnitude and gravity.'

'I am so moved,' Jennifer Nettles said. 'Moved by the grief of those families who lost loved ones. Moved by the pain of those who were injured and the fear of their families.

'Moved by the great heroism as I watched so many brave Indianapolis fans actually run toward the stage to try and help lift and rescue those injured.

'Moved by the quickness and organisation of the emergency workers who set up the triage and tended to the injured.'

Gov. Mitch Daniels called the collapse a 'freakish accident', but he praised the response as instantaneous and highly professional.

'Individual Hoosiers ran to the trouble, not from the trouble, by the hundreds, offering, in many cases, their own professional skills.'

One man who narrowly escaped the falling stage said: 'When the stage collapsed, it missed my foot by about a foot and a half.'

After making sure his girlfriend was alright, he said he helped try to lift the scaffolding off people who were trapped.

Ominous: Fans try desperately to flee as the stage suddenly crumbles above them

Down: The rigging falls directly on top of the hopeless fans who tried to get away

Trapped: The stage falls on top of the people who were trying to run away

'It's the way it fell. There were many people that were trapped underneath it but it didn't land on everybody,' he told local station WTHR.

'It was the most traumatic thing I've ever seen,' Crystal Wilbur told the station. 'Everybody just came in together as a team.'

Tony Francis was in the second row with his wife. He said: 'I saw at least five [possible fatalities] myself.'

'When I left they had just lifted the master speakers and they found two more underneath that.'

Serious incident: The stage fell just before country duo Sugarland were scheduled to perform

Panic: Fans waiting to see Sugarland run away after high winds blew the stage over

Rescue: Emergency crews were called to the scene and workers and set up a command centre to tend to those who were injured

Mr Francis told WTHR his wife 'triaged about ten or twelve people with compound fractures, lacerations, a lot of head injuries and neck injuries.'

Natalie Prater, who is a nurse, said the injured included a child. She described the 'amazing team effort' in the aftermath of the collapse.

'There was no way we could be forewarned that something like this could happen,' she told WTHR.

She was leaving the concert with her husband when the stage collapsed.

'We heard things popping and we took off running. People were pushing. We turned around and saw the stage collapsing.

'Then we ran back, hopped over rafters and went to help as many people as we possibly can.'

She estimated there could be 50 injured or more.

Photographer Darron Cummings was in the audience attending the concert shortly before the collapse.

Rescue: Family members tend to their injured relatives after the horrific accident

Treatment: Indianapolis Fire Department personnel and paramedics tend to the victims of the stage collapse

Fall: About a dozen people are reported to have injuries after the stage collapsed

He said an announcer gave the crowd instructions on how to evacuate if the weather worsened, but said they hoped to get Sugarland, the country band set to perform, on stage soon.

Mr Cummings said he and his friends went ahead and sought shelter in a nearby barn after seeing the weather radar.

'Then we heard screams. We heard people just come running,' Mr Cummings said.

Witnesses told WTHR that some of the injured were in a VIP section in front of the stage known as the 'Sugar Pit'.

The witnesses said a wall of dirt, dust, rain and wind came up the main thoroughfare of the fairgrounds just before the collapse.

'Panic kicked in when they seen the dust bowl coming in from the Midway,' concert-goer Darryl Cox told WTHR.

Aftermath: People continue to be treated as the clean up began last night

Battling: Heavy machinery last night raises up a piece from the collapsed stage

Devastation: The National Weather Service reports portions of the stage were blown into the grandstands

Emergency: Family members tend to their injured relatives as Indianapolis Fire Department personnel and paramedics tend to the victims

Another person at the concert, Emily Davis, told WTHR that there was lightning and the sky had gotten dark but it wasn't raining when the wind suddenly toppled the rigging.

'It was horrible, people were running and going crazy,' she said.

Meanwhile, event organisers have debated continuing with the fair tomorrow in spite of the horrendous tragedy.

Executives said it would go ahead earlier today before a statement suggested it would be cancelled.

Cindy Hoye, the executive director of the Indiana State Fair who was backstage at the time of the collapse, said:

'We are very much in mourning the loss of the victims and we are praying with their families. It's a very sad at the State Fair and our hearts are really breaking.

Performance: Sarah Barielles sings on the stage that collapsed one hour later

Signs: A spokesman gives the crowd instructions on how to evacuate if the weather worsens just two minutes before the stage collapsed

'Personally I was here right backstage and I want to also acknowledge the extraordinary efforts by the joint command center, IMPD, IEMS, IFD, State Police, the State Fair team, where safety is always number one.

'Tomorrow, the fair will reopen. We will open at 8:00 am but we will start with a special public remembrance gathering at 9:00 am on the Free Stage. We ask any of you that would like to attend in joining us in this remembrance and sharing with us in our thoughts and prayers, we'd love for you to be there.'

Mrs Hoye said most of the planned fair programmed would go ahead 'but specific details on the concerts and other activities in the grandstands have not been finalised. We will continue to update you when we have definitive information.'

She added: 'Our hearts are very, very heavy today.'

An hour after the incident, Sugarland tweeted a message to their fans.

'We are all right. We are praying for our fans, and the people of Indianapolis. We hope you’ll join us. They need your strength,' they wrote.

Other musicians also sent condolences to those who had been killed or hurt as a result of the accident.

The morning after: The stage lies a crumbled mess this morning after last night's collapse

Clear up: Labourers have been hard at work, clearing up the mess at the concert site

Kelly Clarkson tweeted: 'I’m not sure what news is correct or not but I heard the people that died or got injured were fans. Please keep all of their families in your prayers. What a horrible thing to happen.'

Blake Shelton wrote:'My prayers to the people at the Sugarland concert in Indianapolis…. Absolutely shocking and hard to comprehend… Beyond belief…'

Jordin Sparks added: 'OMG. I have no words. Please #pray for those who were at the fair in Indy.'